The present invention relates generally to bar codes and more specifically to a method and apparatus for generating and decoding a visually significant barcode.
Barcodes are information carrying graphical patterns designed for easy and reliable automatic retrieval. The most common barcodes are known as one-dimensional barcodes. These graphical patterns vary in a single dimension (e.g. the horizontal dimension), and are constant in the other dimension (e.g., the vertical dimension). One-dimensional barcodes are employed in low information content applications like product index registry (e.g. automatic price tagging and inventory management), or serial number registry (e.g. test-tube tagging in automated medical tests). Common examples of one-dimensional barcodes are those barcodes that are affixed or printed on the packages of items purchased at a supermarket or department store. These barcodes typically can only encode limited information, such as the price of the item and the manufacturer. The items having the barcodes are scanned at a checkout counter to facilitate the tallying up of a total receipt.
In order to convey more information on the same surface area, two-dimensional barcodes were developed. Two-dimensional barcodes involve intricate patterns that vary in both the horizontal and the vertical dimensions. Two-dimensional barcodes are used in applications that require more information contents. For example, two-dimensional barcodes can be used to encode mail addresses for automated mail reading and distribution systems. Mail carrier companies can use the two-dimensional bar code on shipping packages to encode shipper information, recipient information, tracking information, etc. In another example, two-dimensional barcodes can be used to encode the compressed content of a printed page to avoid the need for optical character recognition at the receiving end.
U.S. Pat. Nos. 5,060,980, 5,486,686, and 5,459,307 illustrate an exemplary 2D barcode system. This system utilizes short black bars that have a forward orientation or a backward orientation (e.g., bars that are oriented at either 45% or 135% with respect to a reference) to render the barcode. The two possible orientations of the bar allow information (e.g., 1 or 0) to be encoded therein. This system offers a limited improvement over the traditional 2D barcode in that the appearance of these short black bars while still distracting to the human visual system is less so than the traditional 2D barcode. Consequently, it is asserted by these patents that a barcode utilizing these bars can be placed in the background of a document without excessively distracting a person reading such a document.
Unfortunately, the unsightly appearance of 2D bar codes relegates these bar codes to impersonal commercial and industrial setting regardless of whether the barcode less distracting and can be incorporated into the background of a document. For example, in many consumer applications, the current visually meaningless barcode patterns are prohibitive, since users are more likely to decline the benefits of the application rather than to include a xe2x80x9cbarcodexe2x80x9d on their letterhead.
Another challenge in the design and use of 2D barcodes is the ability to produce barcodes by using office equipment (e.g., printers) that can be subsequently read back also using office equipment (e.g., scanners). For example, the 2D system must address printer and scanner distortions that can vary across different types and manufacturers of the office equipment. It is desirable that the 2D barcode be reliably generated and scanned regardless of the type of machine and the manufacturer of the machine. It is also desirable that the barcode be robust to photocopying (i.e., the barcode can be scanned and information embedded therein decoded from a copy of the originally rendered barcode).
Accordingly, there remains a need for a visually significant 2D bar code that is robust to distortions in the paper path and that overcomes the disadvantages set forth previously.
It is an object of the present invention to provide a method of generating and decoding a barcode with visual significance.
It is a further object of the present invention to provide a barcode pattern with visual significance that is robust to consecutive photocopying and common office document degradation.
It is a further object of the present invention to provide a barcode pattern with visual significance that can be printed and read by standard office equipment.
The barcode system of the present invention includes an encoding module for receiving a message and a logo and generating a visually significant barcode based on these inputs. A decoding module is also provided for receiving an acquired version of a visually significant barcode that may have been degraded in a typical document handling channel (e.g., through the printing, scanning, or copying process) and for recovering the message specified by the visually significant barcode.